Acta Pharmacologica Sinica最新文献

Recent evidence shows that fatty acid synthase (FASN), a key regulator of de novo lipogenesis (DNL), is a promising therapeutic target for metabolic dysfunction-associated steatotic liver disease (MASLD). FASN inhibitors are under advanced clinical trials. In this study, we evaluated the therapeutic efficacy of a novel FASN inhibitor 84-B10 for the treatment of MASLD. RNA-seq analysis showed that FASN was significantly upregulated in PA/OA-treated mouse primary hepatocytes. In silico molecular docking screening combined with biochemical assay, 84-B10 exhibited the strongest FASN-inhibiting effect. We demonstrated that 84-B10 directly bound to the MAT domain of FASN, inhibiting its enzymatic activity and promoting its ubiquitination and proteasomal degradation. In mouse primary hepatocytes, 84-B10 induced Lys48-linked ubiquitination of FASN by recruiting the E3 ligase tripartite motif-containing 28 (TRIM28), leading to FASN protein degradation. In PA/OA-treated mouse primary hepatocytes, 84-B10 (5, 10 μM) dose-dependently ameliorated lipid accumulation and mitochondrial dysfunction. In HFD-fed mice, administration of 84-B10 (5 mg/kg, i.g. every other day for 6 weeks) significantly alleviated metabolic alterations and hepatic lipid accumulation. Our results establish 84-B10 as a novel FASN inhibitor that activating the FASN-TRIM28 axis by binding to the MAT domain, facilitating the proteasomal degradation of FASN. With favorable safety, tolerability, and pharmacokinetic properties, 84-B10 holds promise as a therapeutic candidate for the prevention and treatment of MASLD.

Deletion of IG20 (also known as MADD), which can encode multiple isoforms, causes diabetes in mice by impairing glucose-stimulated insulin secretion. To evaluate the role of IG20 in mediating the therapeutic potential of glinide-class insulin secretagogues, we tested their effects in Ig20/Madd-knockout (KMA1ko) mice. Glucose tolerance tests revealed that repaglinide, mitiglinide, and nateglinide failed to lower blood glucose levels or enhance insulin secretion in KMA1ko mice, suggesting that IG20 deficiency significantly diminishes the therapeutic efficacy of glinides. The functional relevance of at least 6 IG20 isoforms remains to be defined. Interestingly, among the six IG20 splicing isoforms re-expressed in IG20-deficient Min6 cells, only KIAA0358 was capable of restoring glucose-stimulated insulin secretion. Notably, KIAA0358 re-expression also rescued repaglinide-induced insulin secretion in vivo. Further transmission electron microscopy and total internal reflection fluorescence microscopy analyses showed that KIAA0358 significantly promoted insulin granule transport and docking impaired by IG20 knockout. Furthermore, guanine nucleotide exchange assay and GST pull-down demonstrated that KIAA0358 functions as a Rab GEF to convert Rab3A and Rab27A from the GDP-bound to the active GTP-bound state, thereby restoring their interactions with the downstream effector proteins Rim2α and Slac-2a that were impaired by IG20 deficiency. Therefore, by regulating the activation states of Rab3A and Rab27A, KIAA0358 mediated the transport and docking of insulin granules to the plasma membrane. This study also highlights that the genes encoding non-drug target proteins can influence drug efficacy and provides a novel conceptual foundation for precision medicine strategies aimed at reducing drug resistance and enhancing the clinical efficacy of glinides.

Macrophage migration inhibitory factor (MIF) is a cytokine that possesses multiple enzymatic activities, such as keto-enol tautomerase and thiol-oxidoreductase. We previously found that lack of MIF tautomerase activity significantly alleviated high fat diet (HFD)-induced obesity in mice. In this study, we investigated the regulatory mechanisms of MIF tautomerase in obesity. HFD-induced obese mouse model was established. Adipogenic differentiation was induced in mouse preadipocyte cell line 3T3-L1 and mouse adipose-derived mesenchymal stem cells (ADSCs) in vitro. We showed that MIF tautomerase inhibitors ISO-1 or 4-IPP dose-dependently promoted lipid degradation and mitochondrial thermogenesis by enhancing basal oxygen consumption rate and proton leak, accompanied by increased expression of browning markers (UCP1, PGC-1α, DIO2, CD137) in 3T3-L1 cells under adipogenic induction conditions. In HFD-induced obese mice, administration of 4-IPP (5, 10 mg/kg, i.p.) every 2 days for 12 weeks significantly ameliorated HFD-induced obesity, improved insulin sensitivity, and enhanced energy expenditure. In white adipocytes, 4-IPP (1, 5, 10 μM) dose-dependently promoted CD137 expression, and restored CD137-mediated activation of the PI3K/AKT signaling to improve lipid metabolism. CD137 deficiency abrogated the browning effect of 4-IPP in white adipocytes in vitro. CD137^-/- mice exhibited increased susceptibility to HFD-induced obesity and almost abolished the anti-obesity effects of 4-IPP. Simulation of the protein interaction revealed a direct interaction between MIF and CD137: MIF competitively bound to CD137 on white adipocytes with the endogenous ligand of CD137, which was further confirmed by co-immunoprecipitation. Furthermore, 4-IPP and recombinant CD137 protein inhibited the tautomerase activity of MIF in vitro. In conclusion, MIF promotes obesity by binding CD137 through its tautomerase domain, suppressing CD137-mediated the activation of the PI3K/AKT signaling. MIF tautomerase inhibitors disrupt this interaction, restore CD137 function, and enhance adipocyte browning, offering a promising therapeutic strategy for obesity management.

Lysosomal dysfunction exacerbates cardiomyocyte damage in myocardial infarction (MI) by impairing cellular degradation. However, the precise molecular mechanisms driving this pathologic process remain unclear. Lysosomal transmembrane protein 175 (TMEM175) is critical for regulating lysosomal homeostasis. But its pathophysiological implications in post-infarction cardiac dysfunction are not fully understood. By using both gain and loss of function approaches in vivo and in vitro, we discovered that TMEM175 overexpression conferred cardioprotection in MI models. This was evidenced by reduced infarct size, collagen deposition, and myocardial injury, accompanied by restored lysosomal function characterized by increased biogenesis, normalized pH, enzyme activities, and autophagic flux. Conversely, TMEM175 knockdown exacerbated these pathologies. Under hypoxic stress, TMEM175 overexpression in neonatal mouse cardiomyocytes (NMCMs) improved cell viability and corrected lysosomal dysfunction, whereas its knockdown worsened the aforementioned effects. Mechanistically, the reduction of TMEM175 induced by MI increases mammalian target of rapamycin complex 1 (mTORC1) phosphorylation on lysosomal membranes and suppresses the nuclear translocation of transcription factor EB (TFEB), thereby impairing TFEB's transcriptional regulation of lysosome-associated genes. Meanwhile, TMEM175 restoration reversing this cascade, and restoring lysosomal function and autophagic flux.

Sepsis is a life-threatening condition driven by dysregulated immune responses to infection with excessive M1 macrophage polarization-driven cytokine storm which plays a key role in the early progression of sepsis. Targeting macrophage polarization represents a promising therapeutic strategy to improve sepsis outcomes. Conventional drug discovery is hampered by high costs, long timelines and low success rates, posing significant challenges to the identification of novel M1 polarization inhibitors. In this study we constructed a novel transformer-variational autoencoder (TVAE) that integrated complementary molecular fingerprints (extended-connectivity fingerprints, ECFP; molecular ACCess system keys, MACCS keys; 4-point pharmacophore fingerprints, 4-PP) into probabilistic latent distributions to screen for M1-polarization inhibitors. From 5516 natural products, TVAE combined with experimental validation identified ombuin as the top candidate. In vitro, ombuin (10 μM) potently suppressed LPS-induced M1 polarization and pro-inflammatory cytokine (IL-6, TNF-α) release. In cecal ligation and puncture (CLP)-induced mouse sepsis model, administration of ombuin (15, 45 mg/kg, i.p.) significantly improved survival and ameliorated systemic inflammation by modulating the balance of M1/M2 macrophage polarization. By performing LiP-MS assay, we demonstrated that ombuin bound to and activated aldehyde dehydrogenase 2 (ALDH2), thereby suppressing NF-κB p65 nuclear translocation, a key event underlying NF-κB-driven M1 macrophage polarization. Collectively, our AI-driven pipeline efficiently discovers immunomodulatory agents and positions ombuin as a promising lead for sepsis therapy.

Stroke survivors usually suffer from mood and emotional disturbances, especially depression. However, research on poststroke depression (PSD) is limited by the measurement of behavioral despair in animals. The tail suspension test (TST) is a classic method for assessing behavioral despair in mice based on an increased immobility time. Ischemic mice assessed using the classic TST instinctively struggled because of incoordination, which influenced the immobility time and caused misleading results. In this study, we modified the classic TST equipment by introducing a smooth and transparent plate inclined at 60^° to help the suspended mouse maintain its balance during testing, without an obvious reduction in the aversive stress occurring during suspension. Finally, we validated the modified TST using mouse models of chronic mild stress, middle cerebral artery occlusion and PSD. Thus, the modified TST is an efficient method for assessing behavioral despair in mice with impaired motor coordination, especially after stroke.

The best way of treating vasospastic angina pharmacologically is to induce vasorelaxation under hypoxia only. We previously established a new method to quantify the contraction and relaxation of vascular smooth muscle cells (VSMCs) in real time. In the present study, we used this method to screen the effects of chemicals on VSMC dilation under normoxia, and we chose the chemicals with negative results as candidates. Next, we tested the effects of the candidates on VSMC dilation under hypoxia, and we found that cariporide and empagliflozin induced VSMC relaxation under hypoxia but not normoxia. Their effects on hypoxic VSMC relaxation were further confirmed in isolated carotid arteries. We demonstrated that treatment with cariporide (10 μM) or empagliflozin (5 μM) potently inhibited Na⁺/H⁺ exchanger 1, causing intracellular H⁺ accumulation that activated AMPK in VSMCs under hypoxia but not normoxia. KEGG analysis revealed that cariporide upregulated signaling related to AMPK, pH regulation, and Ca²⁺-linked proteins in VSMCs under hypoxia. In a swine model of vasopressin-induced coronary artery spasm, intravenous injection of cariporide or empagliflozin significantly increased coronary blood flow, limited infarct size, and improved heart function, and the protective effects on ischemic hearts were much stronger than those of the currently used vasodilator nifedipine. In conclusion, a novel approach was developed to screen vasodilators that function well under hypoxia but not normoxia. Using this approach, two Na⁺/H⁺ exchanger 1 inhibitors, namely, cariporide and empagliflozin, were identified to treat vasospastic angina as new coronary vasodilators.

Addictive substances transform environmental cues into potent conditioned cues through reward-based associative learning. While visual cues are known to amplify drug-seeking behavior and trigger relapse, the neural circuits mediating their motivational salience remain incompletely understood. Here, we identified the superior colliculus (SC) as a critical encoder of drug-related visual information via gating reinstatement through a defined SC-VTA-NAcore pathway. We established a methamphetamine (MA) self-administration model in mice with fiber photometry, optogenetic, and chemogenetic techniques. Using fiber photometry, we discovered that the monosynaptic SC-VTA pathway exhibited selective activation during exposure to drug-paired visual cues, which demonstrated a stable cue encoding. Optogenetic inhibition of SC-VTA projections completely abolished cue-induced reinstatement, while activation potentiated reinstatement. Transsynaptic tracing confirmed a SC^Glu+-VTA^DA+-NAcore circuit. Bidirectional manipulation of this pathway demonstrated its necessity and sufficiency for controlling cue-triggered reinstatement. Our results establish the SC as a sensory-motivational hub that transforms visual drug cues into relapse-promoting signals through a hardwired midbrain circuit. The discovery of this SC-VTA-NAcore pathway provides both a mechanistic framework for understanding cue-driven addiction and concrete targets for interventions.